Document WO 2009/030867 is known describing an implantable device comprising a textile implant having one surface coated at least in part with a coating comprising a polyvinylpyrrolidone polymer and 4 weight % plasticizer relative to the weight of said polymer. For example, said plasticizer is polyethylene glycol. The polyvinylpyrrolidone polymer is not cross-linked and is therefore soluble in contact with the water contained in the body. This coating is mucoadhesive through the creation of weak bonds of Van der Waals type between the coating and the water contained in the mucus covering the abdominal wall to be reinforced. These weak bonds allow repositioning of the prosthesis without degrading the textile implant but this cannot be obtained by the surgeon without loss of adhesion between the textile implant and the abdominal wall to be reinforced. This loss of adhesion may cause migration of the textile implant intraoperatively and subsequent hernia recurrence. It is therefore recommended, but difficult to achieve for a non-experienced surgeon, to position the textile implant just once on the abdominal wall without any subsequent adjustment in particular by causing said textile implant to slide in a plane parallel to said abdominal wall.
In general it is therefore necessary, after positioning the textile implant on the muscle wall to be reinforced, to adjust the position thereof by causing it to slide in a direction parallel to the plane in which it is contained, or by lifting off the implant. This adjustment allows centering of the textile implant on the wall defect.
Yet this implantable device cannot undergo adjustment of position via sliding or detaching after the initial positioning thereof without deteriorating the adhesion forces between the textile implant and the abdominal wall.
A non-exhaustive explanation of this loss of adhesion would be migration of part of the self-adhesive coating on the abdominal wall at the time of adjusting or detaching the implant.
Other types of bio-adhesives are also known composed of monomers which undergo polymerisation intraoperatively, and optionally also cross-linking, and thereby allow attaching of textile implants onto the abdominal wall via covalent bonds. These intraoperative polymerisation reactions, optionally accompanied by cross-linking, have the disadvantage of always being exothermal thereby generating risks of tissue necrosis. These adhesives are usually sprayed either onto the abdominal wall to be reinforced or onto one side of the textile implant at the time of surgical procedure. It is therefore difficult to control the amount of implanted adhesive. These adhesives are often blood derivatives or cyanoacrylate monomers. Once polymerisation is completed, the surgeon no longer has any possibility of repositioning the textile implant on the abdominal wall via sliding without breaking the covalent bonds and hence deteriorating the adhesion forces of the textile implant on the wall. It is therefore necessary, once a textile implant is joined to the abdominal wall to be reinforced via covalent bonds formed between the bioadhesive coating and said wall, that the textile implant must be correctly centered when first positioned on the wall defect without requiring any adjustments which would deteriorate the adhesion force of the textile implant on the abdominal wall.
Document WO 2012/064821 describes an adhesive partly composed of L-3-4-dihydroxyphenylalanine (DOPA) originating from marine mussels. This adhesive can be arranged in the form of a coating on one of the surfaces of a textile implant. The adhesion between the textile implant and the wall to be reinforced is obtained by covalent bonds. On this account, the textile implant cannot be repositioned post-operatively without deteriorating the surface of the textile implant which received the coating and/or deteriorating the adhesion of the implantable device. The adhesion forces involved between the textile implant coated with the bioadhesive coating and the wall to be reinforced are too strong. Example 35 in document WO 2012064821 shows a rupture load of about 5.5+/−0.8 pounds (2.5 kg+/−0.36 kg) to detach the textile implant from a membrane of bovine pericardium. This separation in the vast majority of cases generates rupture of the textile implant. Even if the surgeon manages to detach the textile implant without deteriorating the textile surface of the implant coated with the bioadhesive coating, and without tearing tissues, this detachment is obtained with definitive rupture of the covalent bonds and hence with complete loss of adhesion forces.
The behavior of a foreign material in contact with living tissues has already been closely examined by several authors. With knitted textile prostheses or implants in polypropylene first an acute inflammatory reaction phase is observed that is exudative and then cellular. After wounding of tissue e.g. abdominal surgery, the normal healing process is initiated. It starts by inflammation, first characterized by vasoconstriction and platelet accumulation. Fibrin is then formed to stop haemorrhaging and lasts about 15 minutes. A parallel phenomenon is observed with subsequent exudation of proteins and plasma cells in the affected region. Cell response occurs between 6 h and 16 h after the initial surgical lesion when the onset occurs of a large amount of polymorphonuclear neutrophils corresponding to the first wave of cell migration. They remain for 3 to 5 days with a peak at 68 h. On Day 1 there is already incursion of monocytes. These are macrophage precursors. Fibroblast proliferation starts about 36 h after the surgical lesion. The macrophages are then activated and leukocytes predominate as from Day 3 when they reach a maximum level and persist until complete healing. This first phase lasts up until the 2nd day and may last up until post-operative Day 4. These different cells are then progressively replaced by fibroblasts the activity of which intensifies with the production of collagen until total colonisation and ingrowth of the prosthesis in about 4 to 6 weeks. There is therefore a critical period before the fibroblast reaction intensifies. It is especially during this period that the stability of the textile implant must be ensured by securing points. A weak inflammatory reaction reflects biological tolerance whereas the intensity of fibroblast activity is the indication of good resistance via the creation of healing tissue of good quality. In addition, the risk of infection is proportional to local inflammatory reaction. The ideal prosthesis would be the one which causes low inflammatory reaction and intense fibroblast activity. The duration of the inflammatory reaction differs according to authors. For some it disappears in a few weeks, for others it persists several months. This reaction is dependent not only on the material used but also on the texture or porosity thereof. If the primary securing of the textile implant is ensured by surgical sutures or merely by inter-positioning of the implant between the planes of the wall, there is a risk of migration or mobilization of the reinforcement over the days following after the procedure. It is conventionally considered that definitive (secondary) securing obtained by healing and ingrowth of the textile implant in the wall is only acquired after 1 month to 6 weeks.
There is therefore a need for an implantable device, in particular for wall repair, comprising a textile implant coated on one of its surfaces and at least in part with a bioadhesive coating which can be repositioned multiple times without loss of adhesion.
There is also a need for an implantable device for which the amount of bioadhesive coating is able to be controlled and reproducible, in particular a bioadhesive coating which can be stored at the same time as said textile implant in a sterilization pouch and hence able to undergo a sterilization step e.g. with ethylene oxide in the gaseous state.